北京市大气气溶胶中含氧有机化合物的研究

Organic Compound Containing Oxygen in Aerosol of Beijing

采用超声萃取、硅胶-氧化铝柱层析分离、气相色谱/质谱联用技术,对北京大气PM10颗粒物中含氧有机化合物进行了鉴定和分析。根据其质量色谱图和特征碎片离子、标准谱库和保留指数,鉴定出酞酸酯、正脂肪醇、正脂肪酸、甾醇、左旋葡聚糖等系列化合物。用内标法进行定量,酞酸酯、左旋葡聚糖、β-谷甾醇、胆甾醇等的浓度分别为545.96～772.46ng/m3、56.98～190.23ng/m3、5.95～16.74ng/m3、2.27～4.52ng/m3,说明北京市大气气溶胶中含氧有机化合物的污染比较严重。左旋葡聚糖、β-谷甾醇季节性变化规律表明,生物质燃烧源对北京的大气污染有一定的影响,且秋季的影响最大。

PM10 samples of Beijing were extracted with ultrasonic agitation and separated by chromatographic column packed with silica gel and alumina. Organic compounds containing oxygen were detected by GC-MS. On the basis of mass chromatogram and characteristics fraction ions, NIST library and retention indices, the series of phthalic acid ester, alkanol, alkanoic acid, sterol and levoglucosan were determined, with concentration of phthalic acid ester, levoglucosan, β sitosterol and cholesterol of 545.96-772.46ng/m3, 56.98 -190.23mg/m2. 5.95 -16.74ng/m3 and 2.27 ~4.52ng/m3 respectively, which showed the pollution of organic compound containing oxygen was serious in Beijing. Seasonal variations of levoglucosan and β-sitosterol indicated that biomass burning contributed to pollution to certain degrees and the influence in autumn was the most.